1. Field of the Invention
This invention concerns an improved catalytic process for producing hydrogen peroxide from hydrogen and oxygen.
2. Background of the Invention
The following references disclose catalytic processes for producing hydrogen peroxide from hydrogen and oxygen. One problem associated with known direct combination processes is that product yields are too low for large scale commercial applications. Improved processes for producing hydrogen peroxide in high concentrations are of significant interest to the chemical industry.
U.S. Pat. No. 3,336,112 issued to Hooper, discloses a process for producing hydrogen peroxide. The process comprises contacting hydrogen and oxygen with a solid catalyst in the liquid phase in the presence of water and a hydrogen peroxide stabilizer, for example, a sequestrative hydrogen peroxide stabilizer. U.S. Pat. No. 3,361,533 issued to Hooper, discloses a process for the production of hydrogen peroxide. The process comprises contacting hydrogen and oxygen with a solid catalyst in the liquid phase in the presence of water, an acid and a non-acidic oxygen-containing organic compound.
U.S. Pat. No. 3,433,582 issued to Campbell, discloses a process for producing hydrogen peroxide. The process comprises contacting hydrogen and oxygen with a solid catalyst in a liquid medium containing water and dissolved boric acid. The reference discloses that there may also be present a second radical, especially a halogen or pseudo-halogen.
U.S. Pat. No. 4,007,256 issued to Kim et al., discloses a process for production hydrogen peroxide by contacting hydrogen and oxygen with a supported palladium catalyst in the presence of water, an organic nitrogen-containing compound and a strong acid. Posplova et al., Russian Journal of Physical Chemistry, 35(2):143-148 (1961) disclose palladium-catalyzed synthesis of hydrogen peroxide from hydrogen and oxygen. Palladium black and palladium deposited on alumina gel, tungstic anhydide, silica gel, and bone charcoal were used as the catalysts.
U.S. Pat. No. 4,009,252 issued to Izumi et al., discloses a process for preparing hydrogen peroxide by a catalytic reaction of hydrogen and oxygen in an aqueous medium containing a platinum-group catalyst. The process is characterized in that the partial pressure of hydrogen and the partial pressure of oxygen in the gaseous phase of the reaction system are maintained at at least 0.5 atmosphere and at least 1.0 atmosphere, respectively, The platinum group catalyst is caused to be present in an amount, calculated as metal, of at least a minimum effective catalytic amount up to 30 mg per 100 mL of the aqeous medium.
U.S. Pat. No. 4,279,883, issued to Izumi et al., discloses a process for preparing hydrogen peroxide by reacting hydrogen with oxygen in the presence of a catalyst in an aqueous medium containing hydrogen peroxide, the improvement which comprises using an aqueous medium which contains dissolved hydrogen and a platinum-group catalyst having adsorbed thereto hydrogen. Supported Pd catalysts with carbon, silica, and a number of other materials are described as equivalents for support purposes.
U.S. Pat. No. 4,335,092, issued to Dalton, Jr. et al., discloses a process for preparing hydrogen peroxide. Hydrogen and oxygen are contacted with a supported palladium catalyst in the presence of methanol. Preferably, the methanol contains up to 1.0% by weight of formaldehyde and is at least 0.001N in hydrochloric acid.
U.S. Pat. No. 4,336,238, issued to Dalton, Jr. et al., discloses an improvement in a process for producing hydrogen peroxide by contacting a mixture of hydrogen and oxygen with a palladium on carbon catalyst in the presence of an acidic aqueous liquid capable of inhibiting decomposition of hydrogen peroxide. The improvement comprises prolonging the useful life of the catalyst by continuous removal of palladium salts produced by solubilization of the catalyst from the acidic aqueous liquid. The medium employed comprises up to 95% by volume of an organic solvent. Moreover, H.sub.2 O.sub.2 concentrations are very low.
U.S. Pat. No. 4,336,239, issued to Dalton, Jr. et al., discloses an improvement in hydrogen peroxide synthesis from hydrogen and oxygen in an acidic medium containing an oxygenated or nitrogenous organic compound using a supported Group VIII noble metal catalyst. The improvement comprises using an oxygen/hydrogen ratio higher than about 3.4 and a catalyst level above 30 mg per 100 mL of medium.
U.S. Pat. No. 4,379,778, issued to Dalton, Jr. et al., discloses improvements in palladium-carbon catalysts for the production of hydrogen peroxide from a mixture of hydrogen and oxygen in the presence of an aqueous liquid capable of inhibiting the decomposition of hydrogen peroxide. The improvement comprises pretreating the catalyst with an aldehyde or ketone, and, preferably, also pretreating the catalyst with a dilute solution of hydrochloric acid. Improved catalysts are obtained by reducing a soluble palladium compound deposited on a high surface area non-graphitic carbon base, in the form of a dried powder, with hydrogen at 27.degree.-200.degree. C.
U.S. Pat. No. 4,389,390, issued to Dalton, Jr. et al., discloses an improvement in a process for producing hydrogen peroxide by contacting a mixture of hydrogen and oxygen with a palladium on carbon catalyst in the presence of an acidic liquid capable of inhibiting decomposition of thus-produced hydrogen peroxide. The improvement comprises prolonging the useful life of the catalyst by continuous removal of palladium salts produced by solubilization of the catalyst from the acidic liquid, preferably by employing high surface area activated carbon as the catalyst support and adsorbent for palladium salts.
The following four publications disclose the danger inherent in producing hydrogen peroxide in the presence of an organic component. Swern, Organic Peroxides, Wiley-Interscience, New York, page 26, (1970) discloses the preparation of peroxy compounds from aldehydes and hydrogen peroxide. The reference discloses that extreme caution should be taken when handling and preparing ketone peroxides, since some are very sensitive and explode with violence. Schumb et al., Hydrogen Peroxide, Reinhold Publishing Corporation, page 179 (1955) describes explosive characteristics of solutions of methyl alcohol, ethyl alcohol, or glycerine in concentrated hydrogen peroxide. Halle, Chemical and Engineering News, 62(27):4 (1984) describes potential hazards associated with organic peroxides. Schwoegler, Chemical and Engineering News, 63(1):6 (1985) describes the shock sensitivity of acetone peroxides.
Commonly-assigned U.S. Ser. No. 726,695, Notice of Allowance mailed June 20, 1986, discloses a method for making hydrogen peroxide from hydrogen and oxygen employing a catalytically effective amount of Pd on adsorbent carbon. The disclosure of this allowed U.S. application is incorporated herein by reference.